(1) Field of the Invention
The present invention relates to the provision of a warning of the proximity of a second vehicle to the operator of a first vehicle and particularly to the avoidance of collisions between marine vessels. Specifically, the present invention is directed to a communications system which interconnects a radar transponder with a VHF radiotelephone so as to establish a radio-linkage with a vessel which has been detected by the keying of its radar transponder. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
(2) Description of the Prior Art
While not limited thereto in its utility, the present invention is particularly well suited for use on marine vessels. Accordingly, this invention will be described below in the environment of a proximity warning system for ships. At the present time most commercial vessels carry a radar and a VHF radiotelephone. The conventional radar systems, even the most sophisticated, detect only the presence and course of a nearby vessel. Any other information must be obtained by establishing verbal communication with the other vessel. This is usually a difficult task since there is no way of first establishing the identification of the other vessel so that it can specifically be called so as, for example, to coordinate maneuvers. In crowded ports the establishment of voice communication between vessels is made even more difficult by the number of vessels.
Many collisions which have occurred in the past could have been avoided if verbal communication had been established between the vessels in time. In crowded ports the amount of time required to establish verbal communication between vessels becomes extremely important. Obviously, enhancing the ability to communicate with nearby vessels, and particularly minimizing the time required to establish such communication, will minimize the chances of collision.